[llvm-commits] [llvm] r160575 - in /llvm/trunk: lib/CodeGen/LiveRangeEdit.cpp test/CodeGen/X86/remat-fold-load.ll
Jakob Stoklund Olesen
stoklund at 2pi.dk
Fri Jul 20 14:29:31 PDT 2012
Author: stoklund
Date: Fri Jul 20 16:29:31 2012
New Revision: 160575
URL: http://llvm.org/viewvc/llvm-project?rev=160575&view=rev
Log:
Avoid folding loads that are unsafe to move.
LiveRangeEdit::foldAsLoad() can eliminate a register by folding a load
into its only use. Only do that when the load is safe to move, and it
won't extend any live ranges.
This fixes PR13414.
Added:
llvm/trunk/test/CodeGen/X86/remat-fold-load.ll
Modified:
llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
Modified: llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp?rev=160575&r1=160574&r2=160575&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp Fri Jul 20 16:29:31 2012
@@ -177,6 +177,19 @@
if (!DefMI || !UseMI)
return false;
+ // Since we're moving the DefMI load, make sure we're not extending any live
+ // ranges.
+ if (!allUsesAvailableAt(DefMI,
+ LIS.getInstructionIndex(DefMI),
+ LIS.getInstructionIndex(UseMI)))
+ return false;
+
+ // We also need to make sure it is safe to move the load.
+ // Assume there are stores between DefMI and UseMI.
+ bool SawStore = true;
+ if (!DefMI->isSafeToMove(&TII, 0, SawStore))
+ return false;
+
DEBUG(dbgs() << "Try to fold single def: " << *DefMI
<< " into single use: " << *UseMI);
Added: llvm/trunk/test/CodeGen/X86/remat-fold-load.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/remat-fold-load.ll?rev=160575&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/remat-fold-load.ll (added)
+++ llvm/trunk/test/CodeGen/X86/remat-fold-load.ll Fri Jul 20 16:29:31 2012
@@ -0,0 +1,143 @@
+; RUN: llc < %s -disable-fp-elim -verify-coalescing
+; PR13414
+;
+; During coalescing, remat triggers DCE which deletes the penultimate use of a
+; load. This load should not be folded into the remaining use because it is not
+; safe to move, and it would extend the live range of the address.
+;
+; LiveRangeEdit::foldAsLoad() doesn't extend live ranges, so -verify-coalescing
+; catches the problem.
+
+target triple = "i386-unknown-linux-gnu"
+
+%type_a = type { %type_a*, %type_b }
+%type_b = type { %type_c, i32 }
+%type_c = type { i32, %type_d }
+%type_d = type { i64 }
+%type_e = type { %type_c, i64 }
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+
+define linkonce_odr void @test() nounwind {
+entry:
+ br i1 undef, label %while.end.while.end26_crit_edge, label %while.body12.lr.ph
+
+while.end.while.end26_crit_edge: ; preds = %entry
+ br label %while.end26
+
+while.body12.lr.ph: ; preds = %entry
+ br label %while.body12
+
+while.body12: ; preds = %if.end24, %while.body12.lr.ph
+ %tmp = phi %type_a* [ undef, %while.body12.lr.ph ], [ %tmp18, %if.end24 ]
+ %ins151154161 = phi i128 [ 0, %while.body12.lr.ph ], [ %phitmp, %if.end24 ]
+ %ins135156160 = phi i128 [ 0, %while.body12.lr.ph ], [ %phitmp158, %if.end24 ]
+ %ins151 = or i128 0, %ins151154161
+ %cmp.i.i.i.i.i67 = icmp sgt i32 undef, 8
+ br i1 %cmp.i.i.i.i.i67, label %if.then.i.i.i.i71, label %if.else.i.i.i.i74
+
+if.then.i.i.i.i71: ; preds = %while.body12
+ %call4.i.i.i.i68 = call noalias i8* @malloc(i32 undef) nounwind
+ %tmp1 = getelementptr inbounds %type_a* %tmp, i32 0, i32 1, i32 0, i32 1
+ %buf_6.i.i.i.i70 = bitcast %type_d* %tmp1 to i8**
+ %tmp2 = load i8** %buf_6.i.i.i.i70, align 4
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* undef, i8* %tmp2, i32 undef, i32 1, i1 false) nounwind
+ unreachable
+
+if.else.i.i.i.i74: ; preds = %while.body12
+ %i_.i.i.i.i72 = getelementptr inbounds %type_a* %tmp, i32 0, i32 1, i32 0, i32 1, i32 0
+ %tmp3 = load i64* %i_.i.i.i.i72, align 4
+ %tmp4 = zext i64 %tmp3 to i128
+ %tmp5 = shl nuw nsw i128 %tmp4, 32
+ %ins148 = or i128 %tmp5, %ins151
+ %second3.i.i76 = getelementptr inbounds %type_a* %tmp, i32 0, i32 1, i32 1
+ %tmp6 = load i32* %second3.i.i76, align 4
+ %tmp7 = zext i32 %tmp6 to i128
+ %tmp8 = shl nuw i128 %tmp7, 96
+ %mask144 = and i128 %ins148, 79228162495817593519834398720
+ %tmp9 = load %type_e** undef, align 4
+ %len_.i.i.i.i86 = getelementptr inbounds %type_e* %tmp9, i32 0, i32 0, i32 0
+ %tmp10 = load i32* %len_.i.i.i.i86, align 4
+ %tmp11 = zext i32 %tmp10 to i128
+ %ins135 = or i128 %tmp11, %ins135156160
+ %cmp.i.i.i.i.i88 = icmp sgt i32 %tmp10, 8
+ br i1 %cmp.i.i.i.i.i88, label %if.then.i.i.i.i92, label %if.else.i.i.i.i95
+
+if.then.i.i.i.i92: ; preds = %if.else.i.i.i.i74
+ %call4.i.i.i.i89 = call noalias i8* @malloc(i32 %tmp10) nounwind
+ %ins126 = or i128 0, %ins135
+ %tmp12 = getelementptr inbounds %type_e* %tmp9, i32 0, i32 0, i32 1
+ %buf_6.i.i.i.i91 = bitcast %type_d* %tmp12 to i8**
+ %tmp13 = load i8** %buf_6.i.i.i.i91, align 4
+ call void @llvm.memcpy.p0i8.p0i8.i32(i8* %call4.i.i.i.i89, i8* %tmp13, i32 %tmp10, i32 1, i1 false) nounwind
+ br label %A
+
+if.else.i.i.i.i95: ; preds = %if.else.i.i.i.i74
+ %i_.i.i.i.i93 = getelementptr inbounds %type_e* %tmp9, i32 0, i32 0, i32 1, i32 0
+ br label %A
+
+A: ; preds = %if.else.i.i.i.i95, %if.then.i.i.i.i92
+ %ins135157 = phi i128 [ %ins126, %if.then.i.i.i.i92 ], [ undef, %if.else.i.i.i.i95 ]
+ %second3.i.i97 = getelementptr inbounds %type_e* %tmp9, i32 0, i32 1
+ %tmp14 = load i64* %second3.i.i97, align 4
+ %tmp15 = trunc i64 %tmp14 to i32
+ %cmp.i99 = icmp sgt i32 %tmp6, %tmp15
+ %tmp16 = trunc i128 %ins135157 to i32
+ %cmp.i.i.i.i.i.i101 = icmp sgt i32 %tmp16, 8
+ br i1 %cmp.i.i.i.i.i.i101, label %if.then.i.i.i.i.i103, label %B
+
+if.then.i.i.i.i.i103: ; preds = %A
+ unreachable
+
+B: ; preds = %A
+ %tmp17 = trunc i128 %ins148 to i32
+ %cmp.i.i.i.i.i.i83 = icmp sgt i32 %tmp17, 8
+ br i1 %cmp.i.i.i.i.i.i83, label %if.then.i.i.i.i.i85, label %C
+
+if.then.i.i.i.i.i85: ; preds = %B
+ unreachable
+
+C: ; preds = %B
+ br i1 %cmp.i99, label %if.then17, label %if.end24
+
+if.then17: ; preds = %C
+ br i1 false, label %if.then.i.i.i.i.i43, label %D
+
+if.then.i.i.i.i.i43: ; preds = %if.then17
+ unreachable
+
+D: ; preds = %if.then17
+ br i1 undef, label %if.then.i.i.i.i.i, label %E
+
+if.then.i.i.i.i.i: ; preds = %D
+ unreachable
+
+E: ; preds = %D
+ br label %if.end24
+
+if.end24: ; preds = %E, %C
+ %phitmp = or i128 %tmp8, %mask144
+ %phitmp158 = or i128 undef, undef
+ %tmp18 = load %type_a** undef, align 4
+ %tmp19 = load %type_a** undef, align 4
+ %cmp.i49 = icmp eq %type_a* %tmp18, %tmp19
+ br i1 %cmp.i49, label %while.cond10.while.end26_crit_edge, label %while.body12
+
+while.cond10.while.end26_crit_edge: ; preds = %if.end24
+ %.pre = load %type_e** undef, align 4
+ br label %while.end26
+
+while.end26: ; preds = %while.cond10.while.end26_crit_edge, %while.end.while.end26_crit_edge
+ br i1 undef, label %while.body.lr.ph.i, label %F
+
+while.body.lr.ph.i: ; preds = %while.end26
+ br label %while.body.i
+
+while.body.i: ; preds = %while.body.i, %while.body.lr.ph.i
+ br i1 false, label %while.body.i, label %F
+
+F: ; preds = %while.body.i, %while.end26
+ ret void
+}
+
+declare noalias i8* @malloc(i32) nounwind
More information about the llvm-commits
mailing list